Only farmers can deliver the following. According to World Bank figures, the global production of urban waste is above 2 billion tonnes and rising. My own experience of composting urban wastes suggests that, technically (if the regulators could come to terms with this) maybe 25% of that could be composted and put to farm land, and possibly more if put to forestry land. If the compost contained only 2% of each of N, P and K, then that would be 10 million tonnes of each. One tonne of N nutrient, made in a modern USA factory, takes 21,000 kWh to make and deliver. So, or the N alone, that would save the use of 210,000,000 kWh of electrical power generation, most of which comes from burning coal and oil. Bearing in mind most N production in the world is several times less efficient than in the USA, and that the rest of the figures err on the side of caution, then recycling urban waste by composting to land would save probably around 1 trillion KWh pa and the associated Carbon dioxide production. As a rough guide, that would save 350,000,000 tonnes of Carbon dioxide being pumped into out atmosphere, every year.
There is a bonus, crops grown on high organic Carbon soils need less irrigation and less crop protection sprays. Cereal crop lodge (fall flat) less. Crops yield a little more. What we need is active, controlled enabling, not ever-increasing suppression and indifference form government.
Bill Butterworth, Land Research Ltd. 18 October 18